Abstract: Hypersonic aircraft requires a good structural performance, good thermal protection properties and the lightest weight. To minimize the weight, an optimization of the thermal structure is made by establishing a one-dimensional thermal transfer model under different thermal conditions, using the aluminum alloy or advanced composite materials as the skin. This paper analyzes the effects of the heat load, the re-entry time, and the skin materials on the TPS weight. Through optimizing the dimensions of the thermal structure, the minimum TPS weight per unit area is calculated. ANSYS simulation results show that the temperature has a prominent effect on the minimum TPS weight per unit area; LI900 and AMHC have an advantage over other TPS concepts; Composite material skin may help reduce the TPS weight. The initial re-entry temperature and the re-entry time have a more significant effect on the rigid ceramic tiles than on the metallic cover insulation.